Having never seen zep live, because i am only 18 today, i can't say i know as much about their live act as you, but i still know zeppelin very well. The one thing i have to disagree with you on is that their music "doesnt hold up after years of exposure to the variety of music we've been listening to". I play bass in a band and for each member in my band led zeppelin is either most or top 5 most influential to each one of us. Albeit my guitarist is no where near as sketchy as him it was jimmy page's producing that made zeppelin so much more powerful. And what about Bonham! Noone can compete with bonham's power on the kit and his sound gets to me everytime.

What you said about plant not letting the music breath is an interesting observation. I can see where your coming from but you still haveto admit to this day noone can sing with the same amount of range and versatility and style as plant. Maybe he was a little busy but i think it fits the music well.

And i do agree that zeppelin created a huge wave of *** in the 80s, but i think thats just a societal tendency. There are amazing bands that come out, and then 10 years later there are bands trying to do the same thing but in a different way and it loses its legitimacy and its power. When you think of it from 65-75 music was amazing. then the 80s were ***. then the 90s were amazing. then the 2000's were ***. Im hoping for a new breakthrough in music in 2010. Im of course REALLY generalizing here to get my opinion across.
let me know what you think